Identifying gene expression and cellular pathways involved in glomerular AL-amyloidosis and correlation with...

The prognosis of myeloma is based on controlling the plasma cell burden and thus, management of the production of monoclonal light chains has improved considerably, expanding survival and quality of life. However, the effects of the monoclonal light chains in the various organs result in alterations that may lead to renal failure. There is a crucial need to ameliorate or abolish renal damage. Organ-based therapies must be developed. Glomerulopathic light chains interact with mesangial cells using the SORL1 receptor and downstream effects lead to divergent mesangial alterations. While the multi-step process occurring when amyloidogenic light chains interact with mesangial cells has been elucidated in the laboratory, gene expression profiles and activated cellular pathways in human glomeruli have not been probed. Mesangial cells from five renal biopsies at different stages of glomerular amyloidosis were interrogated using spatial transcriptomics and compared with those from normal biopsy controls to identify cellular pathways and gene expression changes. The two most significant statistically overexpressed genes (FDR <0.05) when comparing control, early vs late cases were heat shock protein 90AB1 and HSPB1, known to be involved in protein misfolding and aggregation. The overexpressed genes exercise function and regulation over cellular pathways promoting apoptosis, vesicular transport, metalloproteinase activation, collagen degradation, gap junction degradation, GTPase cycle activation, and organelle biogenesis. This data confirmed the results previously reached in the research laboratory. Spatial transcriptomics demonstrated uniquely activated genes and cellular pathways in mesangial cells involved in the initiation and progression of glomerular amyloidosis, uncovering novel genes and new therapeutic targets.